Improve documentation on advtrains.speed.

1 files changed, 10 insertions, 8 deletions

diff --git a/assets/manual/manual.tex b/assets/manual/manual.tex
index ee419e4..69ae2f5 100644
--- a/assets/manual/manual.tex
+++ b/assets/manual/manual.tex
@@ -54,6 +54,7 @@
 \def\luatrue{\texttt{true}}
 \def\luafalse{\texttt{false}}
 \def\luanil{\texttt{nil}}
+\def\luanan{\texttt{nan}}
 \def\advtrains{\textsc{advtrains}}
 
 \newenvironment{centeredtikzpicture}[1][]{
@@ -1310,26 +1311,27 @@ The \texttt{speed} library allows comparison of speed limits, which can be repre
 \item $v \geq 0$, which stands for a speed restriction of $v$.
 \item $-1$ or \luanil, which lifts the speed restriction.
 \end{itemize}
+The use of other values (in particular, \luanan{} and $\pm\infty$) may result in undefined behavior.
 
 Note that the meaning of \luanil{} here differ from the meaning used in signal aspect tables (see section \ref{s:sigasp}): \luanil{} lifts the speed limit instead of keeping it.
 
+For speed limits, it is said that $a < b$ if $a$ is more strict than $b$, and $a = b$ if $a$ and $b$ refer to the same speed limit.
+
 The following entries are present in \texttt{advtrains.speed}:
 
 \begin{apidoc}{\texttt{advtrains}!\texttt{speed}}
-\item \apifunc{lessp}{\var{a},\var{b}} Returns a boolean indicating whether \var{a} is more strict than \var{b}.
-\item \apifunc{greaterp}{\var{a},\var{b}} Returns a boolean indicating whether \var{a} is less strict than \var{b}.
-\item \apifunc{equalp}{\var{a},\var{b}} Returns a boolean indicating whether \var{a} is the same speed limit as \var{b}.
-\item \apifunc{not\_lessp}{\var{a},\var{b}} Returns a boolean indicating whether \var{a} is not more strict than \var{b}.
-\item \apifunc{not\_greaterp}{\var{a},\var{b}} Returns a boolean indicating whether \var{a} is not less strict than \var{b}.
-\item \apifunc{not\_equalp}{\var{a},\var{b}} Returns a boolean indicating whether \var{a} and \var{b} are different speed limits.
+\item \apifunc{lessp}{\var{a},\var{b}} Returns a boolean indicating whether $a < b$.
+\item \apifunc{greaterp}{\var{a},\var{b}} Returns a boolean indicating whether $a > b$.
+\item \apifunc{equalp}{\var{a},\var{b}} Returns a boolean indicating whether $a = b$.
+\item \apifunc{not\_lessp}{\var{a},\var{b}} Returns a boolean indicating whether $a \ge b$.
+\item \apifunc{not\_greaterp}{\var{a},\var{b}} Returns a boolean indicating whether $a \le b$.
+\item \apifunc{not\_equalp}{\var{a},\var{b}} Returns a boolean indicating whether $a \ne b$.
 \item \apifunc{min}{\var{a},\var{b}} Returns the strictest limit of \var{a} and \var{b}.
 \item \apifunc{max}{\var{a},\var{b}} Returns the less strict limit of \var{a} and \var{b}.
 \item \apifunc{set\_restriction}{\var{train},\var{type},\var{val}} Set speed restriction of type \var{type} of \var{train} to \var{val} and update the \texttt{speed\_restriction} field of \var{train} accordingly. \var{Type} defaults to \texttt{main}.
 \item \apifunc{merge\_aspect}{\var{train},\var{asp}} Merge the signal aspect \var{asp} into the speed restriction table of \var{train} and update the \texttt{speed\_restriction} field of \var{train} accordingly.
 \end{apidoc}
 
-For convenience, this manual refers to the functions above as \texttt{speed<}, \texttt{speed>}, \texttt{speed=}, \texttt{speed>=}, \texttt{speed<=}, \texttt{speed/=}, \texttt{speed-min}, and \texttt{speed-max}, respectively. These names are not available in the \texttt{advtrains} table.
-
 \section{Definition tables}\label{s:deftables}
 
 Please refer to \texttt{advtrains/api\_doc.txt} for now.